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Topic: Which number on the scale best correlates with (Read 679 times)

Ouch, well its definitely a 9 here most of the summer if not worse because of air pollution, as I'm doing more naked eye observations, I'm also realizing it's at least partly cloudy a lot more nights than I realized. You don't think much about a partly cloudy night when you aren't observing...

Well let's see hear I'd like to finish this off by comparing the amount of stars we can cover with one hand, naturally in theory only. My hand's on the small side and if I hold it up high it will end blocking on average 5 stars. I heard Betelgeuse is *BLEEP* about this so be careful around him.

Well let's see hear I'd like to finish this off by comparing the amount of stars we can cover with one hand, naturally in theory only. My hand's on the small side and if I hold it up high it will end blocking on average 5 stars. I heard Betelgeuse is *BLEEP* about this so be careful around him.

That's too vague; the star density varies immensely from one part of the sky to another. At a typical suburban location it could easily vary from 20 in and around Orion to zero in parts of Aquarius.

Well you're right about that, especially when you have a washed out horizon to boot. Don't have twenty in any part of the sky here tho. But yes even straight up I can see a variance. I'm working on talking my wife into us moving to one of the few green zones in the country, she seems suprisingly receptive so far but we'll see how long that lasts

Just for sake of discussion I just went outside 5 minutes ago and counted all the stars visible from my backyard with the naked eye. Mind you I only gave myself about two minutes to acclimate to the darkness. Also the moon is quite full but not totally full. In any case I counted every star I could see. The grand total: 27. Yep. I can only see 27 stars with the naked eye. You guys that live in areas with less light pollution don't know just how good you have it. I remember looking up at a full moon sky and seeing countless hundreds of stars still visible. Not here.obin :bangbangbang:

Well last night I looked up and I couldn't see any. So there Of course it was cloudy...Seriously though what time was this? I have to do a test when the weather clears out, but I suspect with the moon out around 8/9 pm I might get similar results. 11pm is when things start getting a lot better.

This was at about 9:30PM local time. It is cloudy now and the mornings are better because many lights which stay on until midnight are finally off. In the morning I estimate that I can see a hundred or so stars with the naked eye.obin

It's a little hard to say. I don't find that Stellarium site helpful at all. But going by John Bortle's original criteria, I would have to classify the skies of my local urban park in Cambridge, MA, as Class 8 on a typical night of good transparency -- which is fairly common here in New England except in the summer.

It correlates pretty well: My limiting magnitude is a bit better than 4.5; I can see M31 and M44 naked-eye, but only with considerable effort, and many of the stars making up the traditional constellations are missing, especially low in the sky.

However, all of the Messier objects are detectable through my 7-inch scope, which is certainly modest by modern standards. And many of them are quite pleasing -- though that's bound to be a subjective judgment.

By the way, this is 4.5 miles from the center of Boston, a metropolis of several million people.

My country home (halfway between Albany, NY and Pittsfield, MA) is harder to classify. It meets most of the criteria for Bortle Class 4. But the zodiacal light is pretty hard to detect, because it just happens that Albany is to the west and Pittsfield is to the east, and those are the directions where the zodiacal light is strongest.

If the dominant light sources were north and south rather than east and west, but the level of light pollution overall was the same, then the zodiacal light would be easy to see, but the southern Milky Way would be much harder to see. On the whole, I think I have the better deal!

The worst location where I have done much time stargazing is Manhattan, which is a good match for Class 9 in most ways. Limiting magnitude just about 4.0, only the Pleiades readily visible naked-eye. (This assumes being on a balcony or in a park where there are few or no lights shining in my eyes.)

However, most of the Messier objects are still visible through modest-sized telescopes, and several of them aside from open clusters are quite attractive. That list is headed by, but not restricted to, the Orion Nebula.

Judging by posts on Cloudy Nights, the biggest problem for most American stargazers is direct glare from nearby lights rather than skyglow. The Bortle Scale is really couched in terms of skyglow, so it's not necessarily applicable in a typical suburban backyard.

This was at about 9:30PM local time. It is cloudy now and the mornings are better because many lights which stay on until midnight are finally off. In the morning I estimate that I can see a hundred or so stars with the naked eye.

It's also because of the sky itself. During evenings in autumn, the southern sky is filled with faint constellations; the only really bright stars are Fomalhaut and Deneb Kaitos.

Before dawn you're seeing the winter sky, which is by far the brightest sector, including the brightest constellation (Orion) and the brightest star besides the Sun (Sirius).

What fraction of the sky can you see, and do you have lights shining directly into your backyard? Those are more likely to limit the number of visible stars than skyglow is.

Tony, I know the new england area quite well. I grew up outside of Providence which is supposedly a red zone on the map, but is definitely not significantly better than my current white zone. Hale-Bopp was an incredible dissapointment just looked like a star and couldn't make out a tail at all. I later lived in the Berkshires on the NY line, and my interest in astronomy had kind of fallen off at that point, but there was not an impressive amount of stars in the night sky and I never saw the Milky Way there. The main difference with my former red zone was there were more stars closer to the horizon but Albany and Pittsfield's light domes didn't make it all that impressive.A somewhat impressive location I spent some time at was central Vermont. I'd guess it was a green zone, didn't see the Milky Way either but there were at around a couple thousand stars visible on a good night I'd say and quite a lot near the horizon as well. The best skies I ever saw where in Eastern Kentucky in the mountains and I can't find the small town on the light map, but I bet it was a blue zone easily. I still didn't see the Milky Way, but that may have just been my lack of experience in having seen it before. An unbelievable amount probably 5,000 stars and tons near the horizon too. Would love to live in an area like that.Anyhow, I've been a bit of gypsy, I also lived in Brookline for a short time, so what you wrote is encouraging to me as I should be able to approach your results with experience. I'm looking to purchase some books are there any particular ones you recommend for white zone people?

Obin, I think our conditions are similar. I think I'm going to look at living in a white zone as a challenge rather than focus on the negative side too much.

That is the way I look at it as well. You have seen the pictures that I can do with basic gear in a heavily polluted suburban yard. The tough part is finding the deep sky objects to photograph. Goto is a necessity for some of them. I only found the whirlpool galaxy using astrophotography. Even through my 10 inch telescope it was pretty much invisible.

I find the greatest challenge in suburban observing to be hunting geostationary satellites. They are extremely dim but finding one is like locating a needle in a hay stack. It is satisfying and lots of fun just to search for the "star" that is not moving.

Yeah that's why I think I'm going sct. If I was in a dark zone I think I'd try the dobsonian. It would be fun to locate objects on my own, but here I think I'd eventually lose interest. Never thought about looking for sattelites or the space station or things like that, but that would be a pretty neat find.

I grew up outside of Providence which is supposedly a red zone on the map, but is definitely not significantly better than my current white zone. Hale-Bopp was an incredible dissapointment just looked like a star and couldn't make out a tail at all.

That surprises me greatly. Hale-Bopp was quite prominent, with a beautiful tail, from here in Cambridge.

<p class="citation">QuoteI later lived in the Berkshires on the NY line ... there was not an impressive amount of stars in the night sky and I never saw the Milky Way there.[/quote]

That surprises me even more. Did you have bright lights around?

I know every road that crosses the MA/NY line, and from every one of them, from Connecticut to Vermont, the Milky Way should be instantly obvious at the state line, as soon as you turn off your headlights. (Obviously, on I90, you would also have to wait for a break in the traffic.)

Sure, there's ample light pollution all around. But the summer Milky Way is ultrabright, shining easily even through pretty heavy suburban light pollution. And nowhere on the MA/NY line could reasonably be called suburban by any normal definition.

<p class="citation">QuoteI'm looking to purchase some books are there any particular ones you recommend for white zone people?[/quote]

I think I was a bad observer in VT because there was a ton of stars there, but didn't see the milky way. I wasn't far from Pittsfield so maybe that's why the Berkshires weren't good? Not exactly a big city so dunno. Yeah Hale-Bopp ticked me off because I was reading the papers about all these great observations and didn't see all that much from where I was. Oh well, maybe Ison will be better for me.Thanks for the suggestion, I'll have to get that book off ebay.